Plumb-level.



No. 802,162.- PATENTED 001'. 17, 1905. W. H. GRAY.

PLUMB LEVEL.

APPLICATION FILED MAR-151905- UNITED STATES PATENT OFFICE.

PLUMB-LEVEL.

Specification of Letters Patent.

Patented Oct. 17, 1905.

Application filed March 15, 1905- $erial No. 250,139.

To all whom it may concern:

Be itknown that LVVILLIAH H. GRAY, a citi- Zen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Plumb-Levels, of whichthe following is a specification.

My invention relates to plumb-levels; and its object is to provide amechanism therefor that is highly sensitive and quickly responsive tovariations.

Another and particular object of the invention is to provide a mechanismwhich will materially multiply in the pointer any movement of theactuating Weight or bob, so that even a slight variation in the positionof the level will move the pointer or pointers to a plainlyperceptibleextent; and the invention consists in the novel construction andarrangement of parts hereinafter described, and particularly pointed outin the claims.

In the drawings, Figure 1 is a transverse section through thecylindrical case and the mechanism therein. Fig. 2 is a face view,plates being removed. Fig. 3 is aview of one face, showing front plateand a portion of its adjacent back plate. Fig. 4 is a perspective viewof the plumb-bob or actuating-weight. Fig. 5 is a perspective view ofthe casingshell minus the end plates. Fig. 6 is adetail view of thestationary or gage pointer. Fig. 7 is a perspective view of theoscillatingpointer frame; and Fig. 8 is a perspective view of thecomplete level, including the stock.

Referring to the drawings, 2 represents the usual form of stock,constructed in any suitable design and of any preferred material,usually wood. Through the stock is out a circular recess for thecylindrical shell 3, which is open at the ends and has aperipheralsightopening 4, as well as openings 5 5 for a supporting spindle 6,carrying the weight or bob 7. The latter has a hook or eye 8 engagingthe spindle 6. v In the lower part of the bob 7 is formed a head orridge 9, extending across the lower face of the bob. This bead is boredfor a bar having projecting ends 10 10, adapted to engage oblongopenings 11 11 in the pointer-frame 12. The latter is fulcrumed upon afulcrum rod or axis 13, supported in suitable openings or otherwise inface-plates 1 1'and'15, closing the ends of the shell 3. mental openings1A In said face-plates are cut segand 15, through which a pointers aremade integral v12 to insure synchronous movements.

scale 16 on each of rear plates 17 18 may be seen. These plates areplaced sufficient distances from the adjacent face-plates to make aspace 19 between plates 14 and 17 and a space 20 between plates 15 and18. A laterally-curved slot 21 is cut through the bob 7 for the fulcrumrod or bar 13 to permit the required swinging movement of the bob.Openings for said rod are also provided in the back plates 17 18, alsoopenings 22 23 for, respectively, the pointers 25 24. These with theframe As shown, this frame consists of the horizontal cross-bar 26 andvertical arms 27 and 28, on which are formed apertured bosses 29 and 30,constituting bearings for the fulcrum-rod 13. The face and back platesmay be secured to the shell 3 in any suitable manner; but I have shownits ends counterbored or rabbeted at 31, which provides shoulders 32 33,engaging the edges of plates 17 and 18, respectively. The face and rearplates may be spaced apart by rings (represented in section at 34: and35, Fig. 1) open at the openings 14: and 15', or the rings may be madecontinuous past said openings, if preferred. The plates 14: 15 17 18 maybe brazed, soldered, or secured in any other suitable manner to theshell 3.

In Fig. 6 is shown an auxiliary pointer or indicator stamped out of apiece of sheet metal to provide a spur or finger 36, bent substantiallyat right angles to the body 'portion 37 in which is a slot 38, engaginga'screw 39,having threaded engagement with a threaded hole 40 in theshell 3. The body portion 37 may be made of spring metal and bentelastically into position against the curved surface of the shell, sothat it may have sufficient frictional engagement with said shell andthejhead of screw 39 to prevent its accidental movement. When astructure surface or structure itself is to be built with a certaindegree of inclination, the pointer 36 may be set opposite a given pointon the scale 16 and the level adjusted until the pointers 24. and 25coincide with or are opposite the pointer 36.

The frame 12 is preferably constructed of light materialsuch as, forinstance, aluminiumso that it will oscillate readily or promptly undercomparatively slight leverage, and in order to obtain the greatestpossible extent of movement of the pointers 24: and 25 for a givenmovement of the bob 7 the distance between the axis of rotation of theframe 12 and the arc of rotation of spindle ends 10 is made acomparatively small fractional part of the total length of radiusbetween said axis and the pointers 24 and 25. By pivoting thepointer-frame independently of the hob, and applying the power of thelatter at its longest arc of rotation and to the frame near its axis ofrotation, the latters movement may be multiplied to any extent necessaryfor a distinctly perceptible movement of the pointers 24 and 25, wherethe inclination of the level is very slight. Plumb-levels having thepointers attached to the bob are practically useless for the purpose ofindicating anything but pronounced variations. If a level-stock is twofeet long, an elevation or depression of one 1 end thereof of one-fourthinch would swing a weight three inches in height only one thirtysecondof an inch at its lower end if pivoted at its upper end. The maximummovement that may be imparted to a pointer when same is on the Weightand confined within substantially the same space as the weight is therefore only one-eighth of the sweep or movement at the end of the two-footstock (or one thirty-second part of an inch) if the movement at the endof the latter is one-fourth of an inch. If the same weight and pointerare pivoted intermediate of their extreme ends, or midway, aone-quarter-inch movement at the end of the stock will produce only asixtyfourth part of an inch movement in the pointer. In either event thepointer movement is imperceptible for all practical purposes. Instead ofimparting a decreased movement to the pointer the present inventionproduces a greater movement in the pointer than at the end of the stock.If the pointer-arm is three inches in length and same is fulcrumedonefourth of an inch from its lower end or the point at which leverageis applied to the arm, the one thirty-second inch movement referred toabove will be increased in pointers 24 and 25 to about eleventhirty-seconds of an inch or three thirty-seconds in excess of themovement at the end of the stock. One-sixteenth part of an inch isplainly perceptible to the average human eye, and a movement to thatextent in the pointers 24 and 25 therefore indicates distinctly theslight inclination from a level line of about one foot rise ordepression for a distance of about ninety feet. Now if the builder,knowing the percentage of grade or inclination that must be maintained,desires to set the level accordingly he will move the pointer 36 to theproper point on the scale and adjust the structure or level so as tobring the pointers 24: and 25 in line with the pointer 36. As statedabove, the substantial movement of one-sixteenth of an inch willindicate an incline or grade only slightly over one per cent. With anordinary combination bob and indicator or pointer pivoted centrally noordinary incline could be perceptibly recorded at the pointer, and amovement of one-sixteenth of an inch would require an inclination ofprobably not less than ten per cent.

As may be noted by reference to Figs. 1 and 8, the pointers can be seenfrom both sides and the top of the level, the stock 2 being providedwith an opening I, which registers with the opening 4 in the shell 3.

The openings 14 and 15 may be covered with glass in the usual manner,and as the only portions of the case which require a glass ortransparent portion are the comparatively small spots opposite theindicatorpoints and scales 16 the liability of breakage is greatlyreduced, and the mechanism is well protected by the metallic casecomprising shell 3 and face-plates 14 and 15., all preferablyconstructed out of brass.

Numerous modifications may be made in the details of constructionwithout departing from the spirit of my invention, and

I claim as new and desire to secure by Letters Patent 1. In aplumb-level, the combination with a recessed weigh t, of a pointer-framepivoted to said weight, said frame being arranged around said weight andfulcrumed upon a rod passing through the recess in said weight, saidWeight and frame being arranged to multiply in the former a givenmovement in the latter and to indicate said movement at opposite sidesand the top of said weight.

2. In a plumb-level, the combination with a recessed stock, of a shell3, a weight or bob arranged to be concealed within said shell, dialsarranged on opposite sides of said weight, a frame having pointersarranged to move over the outer faces of both of said dials, said framearranged around said weight and consisting of a single and comparativelyrigid member to insure synchronous movements of its pointers, saidWeight and frame being mounted and pivoted together so as to multiply inthe pointers a given movement of the weight.

3. In a plumb-level, the combination with a recessed stock, of a casing,a swing-bob or weight, dials in the ends and an opening in the top ofsaid casing, said dials arranged to conceal otherwise exposed portionsof said weight, a fulcrumed frame pivoted to and passing partly aroundsaid weight, said frame having pointers which cooperate synchronouslywith the faces of all of said dials.

4. In a plumb-level, the combination, with a recessed stock, of aplurality of dials, an oscillating frame having arms the free ends ofwhich constitute pointers, an oscillating weight pivoted to said arms atsubstantially its maximum arc of swing, said arms being fulcrumedsubstantially in the plane of the cord of said maximum arc, said weightbeing confined between the dials while said arms are arranged tocooperate with the outer faces of said dials.

5. In a plumb-level, the combination with a recessed stock, of a shell,a recessed weight suspended from the upper part of said shell, dials atthe ends of' said shell and a sightopening arranged at right angles tosaid dials, a frame pivoted to said weight and fulcrumed upon a rodpassing through the recess in said weight, said frame consisting of asingle member the ends of which constitute pointers which cooperate withsaid dials and move opposite said opening.

6. In a plumb-level, the combination with a stock, of a casing having asight-opening, dials in the vertical sides of said casing, a recessedactuating-weight pivoted in the top of said casing, a pointer-framecooperating with said dials and sight-opening, and a fulcrumrod for saidframe extending through said recess in said weight, said weight andpointerframe being pivoted together in a plane below the plane of saidfulcrum-rod.

7. In a plumb-level, in combination, a shell 3 having front plates 14and 15 with dialopenings therein and sight-opening 4, a dial 16 oppositeeach of said openings, the pointerframe 12 cooperating with said dialsand opening 4, and the weight 7 arranged to swing said frame so that theupper or pointer ends thereof swing several times the distance throughwhich said weight itself swings.

8. In a plumb-level, in combination, a shell 3 having front plates 14and 15, with dialopenings 14 and 15, and back plates 17 and 18 carryingscales 16, said shell having also a sight-opening 4, the frame 12 havingarms 27 and 28 and horizontalpointers 24 and 25, the weight 7 pivotedsubstantially at the arcs of swing of pointers 24, 25, said Weighthaving the bead 9 and recess 21, and said frame fulcrumed near the arcof maximum swing of said weight 7, on the fulcrum-rod 13 extendingthrough said recess in said weight.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

WILLIAM H. GRAY. .l/Vitnesses:

FRED L. KoEHLER, RoB'r. KLOTZ.

